Fetching documents from Mongoose inside a map function returns Promise pending as well as the data
Answer a question So I have this array of strings which I'm using as filter to fetch documents from MongoDB using Mongoose. I'm successfully getting the data back from the db, but it is also returning
Answer a question
So I have this array of strings which I'm using as filter to fetch documents from MongoDB using Mongoose. I'm successfully getting the data back from the db, but it is also returning Promise { <pending> }
on the console even though I'm wrapping the map function with Promise.all
.
Please note that this map function is nested inside two level deep for in
loops which I'm leaving out for simplicities sake.
Suppose this is the array of strings:
const subCategories = [ 'Politics', 'Entertainment' ];
And this is the map function:
const subCategoryID = await Promise.all( subCategories.map( async item => {
try {
const data = await SubCategory.findOne( { subCategory: item } );
return data;
} catch( e ) {
throw err;
}
}));
console.log( subCategoryID );
Promises make my head spin. I have tried learning Promises more than 5-6 times in the last 1-2 years and it still confuses me. So if you can, please provide a solution with Async/Await.
Answers
If you only want the result, Try this approach:
const subCategories = [ 'Politics', 'Entertainment' ];
const queries = subCategories.map((i) => {
return { subCategory: i };
});
const subCategoryID = await SubCategory.find({
$or: queries,
});
console.log(subCategoryID);
using operator is explained in mongodb manual:
The
operator performs a logical OR operation on an array of two or more
<expressions>
and selects the documents that satisfy at least one of the<expressions>
.
more about it here.
In mongoose, you can use it in any find
methods.
for explanation about your promise, sorry I can't help.
Please mark answered if this solves your problem.
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